AA 6486 then OO 9915 at O'Hare
Detroit → Chicago → Milwaukee
Timetable, Chicago time
17:29AA 6486 from Detroit at the gate
13:00OO 9915 to Milwaukee leaves the gate
19 h 31 apart on the timetable, overnight
OO 9915 leaves 19 h 31 after AA 6486 arrives on the timetable: more than half a day, so not a connection we count.